1. Field of the Invention
The present invention relates to a print controller, a print control method, and a print control program.
2. Description of the Prior Art
Recent printers are utilized in so-called press simulation wherein a publication such as a catalog is printed on trial by the designer before a printing service provider prints it. In conventional press simulation (e.g. Japanese Patent Prepublication No. 2000-62253 (page 3)), color management is implemented. This is a mechanism for outputting substantially constant colors independently of differences in printing medium or printer. More specific description will be given. Profiles wherein the color components in input image data and the color components in output image data can be transformed into coordinates in a non-equipment-dependent color space, such as Lab, are stored beforehand. (* is usually affixed to L, a, and b, like L*a*b* but it is omitted in this specification for simplicity. This is the same with the following description.) Profiles correspond to printing media and the like with which print operation is performed. By using a profile meeting printing conditions, a designer's print result and a printing service provider's print result can be matched with each other.
In printers, inks of a plurality of color components are recorded, and a plurality of colors are rendered by subtractive color mixture. To meet users' needs, the above-mentioned press simulation is sometimes constituted so that print operation can be performed using only a single ink or an ink in a specific color. However, if with respect to a pixel whose color components are the same as this ink, color conversion is carried out referring to a profile, a problem arises. The color is not converted into a color for which only the single ink or the ink in the specific color is specified. Instead, it is converted into a color rendered by a combination of a plurality of ink colors different in hue. Consequently, when use of only a single ink is specified, color print operation is sometimes performed as follows: with respect to pixels wherein only the same color components as this ink have a gradation value greater than 0, print operation is performed without color conversion referring to a profile. (That is, print operation is performed without changing gradation values.)
If print operation is performed using only a single ink, a problem results. If a profile is referred to, it is impossible to use only the single ink. If a profile is not referred to, the color tone differs from that rendered when with respect to the single color, color conversion is carried out referring to a profile. As an example, it is assumed that an attempt is made to print a single color of K (black). If a profile is referred to, K can be rendered by a combination of three colors of CMY (C: cyan, M: magenta, Y: yellow). Black rendered by this combination and black rendered singly by K ink are different from each other in color tone. Especially, when gradations are printed, differences in color tone are remarkable.